EDDY CURRENTS in a 8 Way TP+N DISTRIBUTION BOARD

[headscrating]

Hi All,

Eddy currents in a 3 phase 8 way distribution board?

on the left hand side i have 5 x 50mm bushes,neutrals and earths enter the lower 2 bushes and the feeds go str8 to a contactor expansion the feeds from the distribution board leave through the other 3 bushes to supply the contactors.Will eddy currents be in the metal side of distribution board?.
If so:
Can you take a measurement with an ammeter(what is a dangerous eddy current)
could i wire a neutral loop through the bushes to cancel out eddy currents(would this cancel out eddy currents)
or is it a simple case of cutting a slot (which would involve removing circuits to do)

 

[RF Lighting]

If you're wondering why you haven't got any replies, it is because your pose makes no sense at all.

Try writing it again, but this time use plain clear English to explain what you have, and what you are trying to acheive.

Don't use abreviations, and don't use txt spk. If you can't be bothered to ask the question properly, why should we be bothered to reply?

A diagram or a photograph of what you are tying to do will also help us no end.

 

[ricicle]

The only way to remedy it and comply with regulations is to have all the conductors from the circuit passing through the same bush or cut the slots. Bear in mind though that if the latter weakens the structure of the dis. board then that would be classed as poor workmanship.

 

[RF Lighting]

You can't cut slots if bushes and couplings are used anyway.

 

[Adam_151]

You can't cut slots if bushes and couplings are used anyway.

It depends on wether he has actually got a coupler in there, or just bush spaced off with a locknut. As long as the mild steel of the DB (and whatever enclosure is on the other side) is slotted to make one hole, AFAIK the brass of the bush shouldn't be a problem as its not ferromagnetic, and I think lock nuts are made from alumimum which likewise shouldn't give any issues.

 

[XtraRaptor]

Hi All,

Eddy currents in a 3 phase 8 way distribution board?

on the left hand side i have 5 x 50mm bushes,neutrals and earths enter the lower 2 bushes and the feeds go str8 to a contactor expansion the feeds from the distribution board leave through the other 3 bushes to supply the contactors.Will eddy currents be in the metal side of distribution board?.
If so:
Can you take a measurement with an ammeter(what is a dangerous eddy current)
could i wire a neutral loop through the bushes to cancel out eddy currents(would this cancel out eddy currents)
or is it a simple case of cutting a slot (which would involve removing circuits to do)

Not sure about measuring the current, but I used to do surveys with a thermal imaging camera, this was one thing I could pick up on in sub-stations as the eddy currents produced heat in the gland plates.

If your installation has a gland plate you could link all the holes with a saw slot (using a jigsaw), or you can replace the plate with something non-ferrous.

 

[headscrating]

Any thoughts of wiring a neutral loop through these holes?

 

[RF Lighting]

It's not going to acheive anything.

 

[headscrating]

i read this back to myself and pictured a db with the holes on the left side with the cables running through separate holes there is an extension chamber holding contactors so the lighting feeds goes to this not the mcb's

if your that electrically minded to think about the problem the dont post

thanks

thought this was a trade forum not a DIY post silly replies forum

 

[RF Lighting]

It's a DIY forum. The clue is in the website name

We will try and help with trade questions if only we could understand what you are jabbering on about.

 

[Adam_151]

Draw us a picture of what you mean OP, as the written descriptions are not clear!

As a quick check to see if its problem if you can't think through it from a design POV is to switch all the loads on and put your clamp ammeter around all the conductors going through a particular hole, if it reads anything above zero then you have got a potential issue there

 

[ricicle]

I think lock nuts are made from alumimum which likewise shouldn't give any issues.

They are usually galvanised or black enamelled steel so you would have to specify aluminium

 

[headscrating]

THANKS for your inputs

All sorted now as regs say very little on the subject but this is only an issuse when a load of 125amps or greater is being pulled through a circuit

 

[RF Lighting]

Where did you get that figure from?

 

[ricicle]

this is only an issuse when a load of 125amps or greater is being pulled through a circuit

So a cable carrying 125A through a 50mm bush will be worse than a cable carrying 63A through a 16mm hole will it ?